Galton's whistle is also called as Dogs whistle or silent whistle, is a type of whistle that emits sound in the ultrasonic range, which people cannot hear but some other animals can, including dogs and domestic cats, and is used in their training.

Our Ex. Prime Minister Rajiv Gandhi was Pilot by profession before he entered politics.

The world’s largest tropical rainforest Amazon rain forests are called "Lungs of the Earth". It is so called because it produces 20% of the Earth's oxygen, and is also a vast carbon sink, absorbs more than 1 billion tons of atmospheric carbon which is emitted by the burning of fossil fuels annually.

Rajya Sabha is a permanent body and is not subject to dissolution. However, one third of the members retire every second year, and are replaced by newly elected members.